1. Technical Field
The present disclosure relates in general to well control and intervention methods and systems. More particularly, the present disclosure relates to well control and intervention methods and systems used for well completion, flow testing, well stimulation, well workover, diagnostic well work, bullheading operations, plugging wells and/or abandoning wells, where subsea trees or wellheads are installed. In an embodiment, these systems and methods are deployed using a slickline, e-line, coiled tubing or jointed tubulars, for example.
2. Background Art
The Current practice for well control and intervention for wells completed with horizontal subsea trees is to use a Subsea Test Tree (SSTT) system. For vertical subsea trees a Completion Work-Over Riser (CWOR) system is typically used. SSTT and CWOR systems are complicated mechanically, and not readily available. The rental cost per well intervention for a SSTT is approximately $US 5 million to 10 million whereas the purchase cost for a CWOR, which is not typically rented, is $US 55 million to $75 million.
U.S. Pat. No. 6,053,252 discloses an intervention apparatus that is said to essentially replicate the pressure control functions of a blowout preventer (BOP) stack. The intervention package consists of five main parts: a lower first wellhead connector which connects to the exterior of the tree mandrel; a cylindrical housing formed of lower housing and upper housing and which define an internal diameter which is substantially the same as the tree mandrel interior diameter; an upper second tree connector; a sub-sea test tree with two ball valves located within the upper part of the housing and also within the upper connector, and a proprietary tree cap intervention tool disposed in the lower part of the housing and the top part of the first connector. The housing parts are coupled together by a circular connector clamp such as a Cameron clamp and the top connector is coupled to a stress joint which forms the bottom end of the tubing riser; the stress joint also receives coiled tubing.
As explained U.S. Pat. No. 6,053,252, after testing the pressure integrity of the system, the test tree valves are opened, a wireline tool is run to pull the plug from the tree cap and a second run is made to pull a plug from the tubing hanger. Wireline can be run if needed, for example to insert a valve to facilitate flow or to provide a logging function. Communication with the surface through the annulus is a complicated procedure achieved by running a tubing annulus bridge on a wireline. This allows an annulus port inside the horizontal tree to be connected to an annulus void within the intervention package while being separated from the main bore, thus allowing control of the annulus for various functions such as pumping or stimulation operations via the crossover facility in the tree cap running tool, the annulus port and the coiled tubing riser to surface. The tubing annulus bridge is generally cylindrical and has first and second concentric elements which are of different lengths. The interior longer element and the outer and shorter length element define an annular cavity which opens at the top end of the bridge to register with an aperture disposed in the bottom of the tubing hanger running/tree cap intervention tool. This aperture is closeable by a sleeve which is hydraulically actuatable to move longitudinally within an annular cavity so as to cover or uncover the aperture.
It would be advantageous if a well intervention system and method could be developed that meets or exceeds the prior art systems and methods, and is also less complicated in operation and less costly to manufacture and rent than existing prior art systems and methods. The systems and methods of the present disclosure are directed to these needs.